An optical system for illuminating and viewing a target, which may include for example a target, a source of illumination of the target and an imager or other device for receiving the light remitted from the target, can be defined by or analyzed in light of, for example, an illumination axis and optical axis that may converge at the target.
Such an optical system may be as simple as an operator of an illumination source viewing a target, wherein the operator embodies the imager, and is the unit receiving the light remitted from the target. An example of such an optical system is an operator of a vehicle, inside the vehicle and looking out at an illuminated target such as a road or tunnel walls.
Other optical systems may include other components such as automated processors as imaging devices receiving the light remitted from a viewed target. Examples of such optical systems can be found in diagnostic apparatuses such as endoscope devices. The endoscopes described in the art may include, for example an image pickup element and an illuminating element for illuminating an examined target, and other components.
For some optical systems it may be advantageous to have the illuminating element and receiving element contained within a single compartment, for example behind a single optical window.
In devices typically used to view the gastrointestinal tract, such as endoscopes, when the device is inserted into the intestine the field of illumination may be obscured by folds of the intestine wall collapsing on the tip of the endoscope. This and other problems may be solved by insufflating air in the intestine. Air insufflation may inflate the intestinal walls, flatten the folds that are naturally present in the intestine wall, and remove potential obstruction from both the illumination source(s) and from the imager.
Air insufflation of the intestine may change the normal physiological conditions of the intestine. In an unmodified environment viewing conditions in the intestine may be similar to underwater viewing. Air insufflation may modify these conditions.